Consumer-grade 3D printers are becoming commonplace in households and businesses for printing tangible objects. 3D modeling programs, including some advanced graphic programs such as Adobe® Photoshop®, can be employed to either create a 3D model from scratch, view and manipulate a 3D model, or in some cases, generate a 3D model from a scanned input. The 3D model is a virtual design for a particular object and is typically provided in a digital file. When a 3D model is ready for fabrication, the 3D model can be printed by a 3D printer to create a tangible replica of the 3D model.
Consumer-grade 3D printers employ a cost-effective method of manufacturing called fused deposition modeling. Fused deposition modeling relies on an additive principle of melting and laying down a fast-cooling thermoplastic material, typically in filament form, into layers. Most consumer-grade 3D printers that employ fused deposition modeling processes rely on the 3D modeling program to cut the 3D model into many horizontal cross-sections, herein also referred to as slices. These slices can then be interpreted by the 3D printer to print the slices upon one another until the desired object is formed. The printing of each slice can be analogized with the printing of a 2D image using an inkjet printer. In more detail, a standard inkjet printer can print a 2D image by laying ink onto paper, line-by-line, until each line is laid on the paper to create the desired image. Similarly, consumer-grade 3D printers can print each slice as a 2D image by melting and laying the thermoplastic material onto a first surface or preceding slice, line-by-line, until each line is laid to create the desired slice.
As consumer-grade 3D printers are becoming larger, so are the objects being printed. While fused deposition modeling is a well-refined methodology for printing smaller objects, the printing of larger objects can lead to problems with structural integrity and material waste. More specifically, the printing of larger objects introduces issues involving the bending and cracking of thermoplastic material when long lines are printed. When a melted thermoplastic material is printed, the material will contract as it cools. When a long line is printed using a single pass of the 3D printer, the cooling and contraction time along the length of the line is directly proportional to the length of the line. As such, the longer the printed line, the greater the likelihood of bending and cracking. A similar problem occurs when printing long lines on top of one another. For instance, an earlier printed line could cool and contract far before a newly printed line, sitting atop the earlier printed line, begins to cool. As a result, the earlier printed line's contraction can cause further bending or cracking in the structure.
Several solutions have been contemplated to avoid bending and cracking when 3D printing a large object. A first contemplated solution is to print the object as a solid. Concerns of bending and cracking can be minimized as each printed line has more bonds across its surface area due to adjacency with a plurality of printed lines. The process of printing solid objects is inefficient, however, as most objects are printed hollow to reduce print times and material waste. Other solutions have employed support structures, including lattices interior to a shell portion, or employing “rafts” to support a bottom portion. Some support structures (i.e., rafts) can be wasteful, however, and can also take away from the pleasing aesthetics of a 3D printed object.